public static<T> String getData(String fileName,Class<T> data)如何调用
时间: 2024-02-01 08:14:10 浏览: 19
可以这样调用:
```
String fileName = "data.json";
Class<MyData> dataClass = MyData.class;
String data = getData(fileName, dataClass);
```
其中,`MyData` 是你定义的数据类,`data.json` 是存储数据的 JSON 文件名。调用这个方法会返回一个 `String` 类型的数据,你可以根据需要进行解析。
相关问题
public static<T> String getData(String fileName,Class data)如何调用
您可以按照以下方式调用该方法:
1. 首先,需要将该方法所在的类导入到您的代码中。
2. 然后,您需要创建一个类来存储您想要读取的数据。例如,如果您想要读取一个JSON文件,那么您需要创建一个类来表示该JSON文件中的数据。
3. 接下来,您需要将该类传递给该方法作为参数。例如,如果您创建了一个名为`Person`的类来表示JSON文件中的人员信息,那么您可以按照以下方式调用该方法:
```
String fileName = "person.json";
Class<Person> personClass = Person.class;
String data = getData(fileName, personClass);
```
在这个例子中,我们将文件名设置为`person.json`,并将`Person`类传递给`data`参数,以告诉方法我们想要读取的数据类型。
4. 最后,方法将返回一个字符串,其中包含从文件中读取的数据。您可以根据需要对此数据进行进一步的处理。
请注意,由于该方法使用了Java的泛型机制,因此您需要在调用该方法时指定数据类型。
<h1>上传/下载文件</h1> <form method="post" action="/file/upload" enctype="multipart/form-data"> <input type="file" name="file" id="fileInput"/> <input type="submit" value="上传" /> </form> <hr> <form method="post" action="/file/download" > <input type="text" name="fileName" placeholder="请输入文件名" /> <input type="submit" value="下载" id="downloadBtn" /> </form> public class SFTPUtil { private static final String host = "10.60.0.160"; private static final int port = 22; private static final String username = "root"; private static final String password = "Z20"; private static Session session = null; public static void connect() throws Exception { } public static void upload(MultipartFile file, String path, String fileName) throws Exception { } public static boolean download(HttpServletResponse response, String path, String fileName) throws Exception { } @Controller @RequestMapping("/file") public class FileController { private static final String UPLOAD_PATH = "/data/sftp/adtuser1/upload/winbidding/"; private static final String DOWNLOAD_PATH = "/data/sftp/adtuser1/upload/winbidding/"; @PostMapping("/upload") @ResponseBody public ModelAndView upload(@RequestParam("file") MultipartFile file) { } @PostMapping("/download") public ModelAndView download(@RequestParam("fileName") String fileName, HttpServletResponse response) throws Exception { } 数据库有host port username password UPLOAD_PATH DOWNLOAD_PATH csmc字段,把上边写死的改成数据库查询,前台页面增加csmc字段下拉框,根据csmc字段把查出来的配置数据完成上传下载功能,用的mysql数据库,把代码改好写出来
首先需要在数据库中创建一个表,用于存储SFTP连接的相关信息:
```sql
CREATE TABLE sftp_config (
id INT PRIMARY KEY AUTO_INCREMENT,
csmc VARCHAR(50),
host VARCHAR(50),
port INT,
username VARCHAR(50),
password VARCHAR(50),
upload_path VARCHAR(255),
download_path VARCHAR(255)
);
```
然后在Spring Boot项目中创建一个SFTPUtil类,用于实现SFTP上传和下载功能:
```java
import com.jcraft.jsch.*;
import org.springframework.web.multipart.MultipartFile;
import java.io.*;
import java.util.Properties;
public class SFTPUtil {
private String host;
private int port;
private String username;
private String password;
private String uploadPath;
private String downloadPath;
private Session session;
public SFTPUtil(String host, int port, String username, String password, String uploadPath, String downloadPath) {
this.host = host;
this.port = port;
this.username = username;
this.password = password;
this.uploadPath = uploadPath;
this.downloadPath = downloadPath;
}
public void connect() throws Exception {
JSch jsch = new JSch();
session = jsch.getSession(username, host, port);
session.setPassword(password);
Properties config = new Properties();
config.put("StrictHostKeyChecking", "no");
session.setConfig(config);
session.connect();
}
public void upload(MultipartFile file, String fileName) throws Exception {
ChannelSftp channel = (ChannelSftp) session.openChannel("sftp");
channel.connect();
channel.cd(uploadPath);
InputStream inputStream = file.getInputStream();
channel.put(inputStream, fileName);
inputStream.close();
channel.disconnect();
}
public boolean download(HttpServletResponse response, String fileName) throws Exception {
ChannelSftp channel = (ChannelSftp) session.openChannel("sftp");
channel.connect();
channel.cd(downloadPath);
SftpATTRS attrs = channel.lstat(fileName);
if (attrs == null) {
channel.disconnect();
return false;
}
response.setHeader("Content-Disposition", "attachment; filename=\"" + fileName + "\"");
OutputStream outputStream = response.getOutputStream();
channel.get(fileName, outputStream);
outputStream.flush();
outputStream.close();
channel.disconnect();
return true;
}
}
```
然后在Spring Boot项目中创建一个FileController类,用于处理文件上传和下载请求:
```java
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.multipart.MultipartFile;
import javax.servlet.http.HttpServletResponse;
import java.util.List;
import java.util.Map;
@Controller
@RequestMapping("/file")
public class FileController {
@Autowired
private JdbcTemplate jdbcTemplate;
@PostMapping("/upload")
@ResponseBody
public String upload(@RequestParam("file") MultipartFile file, @RequestParam("csmc") String csmc) {
try {
// 从数据库中获取SFTP连接配置信息
String sql = "SELECT * FROM sftp_config WHERE csmc = ?";
Map<String, Object> map = jdbcTemplate.queryForMap(sql, csmc);
String host = (String) map.get("host");
int port = (int) map.get("port");
String username = (String) map.get("username");
String password = (String) map.get("password");
String uploadPath = (String) map.get("upload_path");
String fileName = file.getOriginalFilename();
// 使用SFTP上传文件
SFTPUtil sftpUtil = new SFTPUtil(host, port, username, password, uploadPath, null);
sftpUtil.connect();
sftpUtil.upload(file, fileName);
return "上传成功";
} catch (Exception e) {
e.printStackTrace();
return "上传失败";
}
}
@PostMapping("/download")
public void download(@RequestParam("fileName") String fileName, @RequestParam("csmc") String csmc, HttpServletResponse response) throws Exception {
// 从数据库中获取SFTP连接配置信息
String sql = "SELECT * FROM sftp_config WHERE csmc = ?";
Map<String, Object> map = jdbcTemplate.queryForMap(sql, csmc);
String host = (String) map.get("host");
int port = (int) map.get("port");
String username = (String) map.get("username");
String password = (String) map.get("password");
String downloadPath = (String) map.get("download_path");
// 使用SFTP下载文件
SFTPUtil sftpUtil = new SFTPUtil(host, port, username, password, null, downloadPath);
sftpUtil.connect();
boolean result = sftpUtil.download(response, fileName);
if (!result) {
response.getWriter().write("文件不存在");
}
}
@GetMapping("/csmcList")
@ResponseBody
public List<String> getCsmcList() {
// 从数据库中获取所有的csmc字段
String sql = "SELECT DISTINCT csmc FROM sftp_config";
List<String> csmcList = jdbcTemplate.queryForList(sql, String.class);
return csmcList;
}
}
```
最后,在HTML页面中加入下面的代码,即可实现文件上传和下载:
```html
<h1>上传/下载文件</h1>
<form method="post" action="/file/upload" enctype="multipart/form-data">
<input type="file" name="file" id="fileInput"/>
<select name="csmc" id="csmcSelect"></select>
<input type="submit" value="上传"/>
</form>
<hr>
<form method="post" action="/file/download">
<input type="text" name="fileName" placeholder="请输入文件名"/>
<select name="csmc" id="csmcSelect"></select>
<input type="submit" value="下载" id="downloadBtn"/>
</form>
<script>
// 获取csmc列表
$.get("/file/csmcList", function (data) {
var csmcSelect = $("#csmcSelect");
for (var i = 0; i < data.length; i++) {
var option = $("<option>").val(data[i]).text(data[i]);
csmcSelect.append(option);
}
});
</script>
```